The average prospective terrorist / criminal etc isn't going to be able to set up TLS. If they encrypt their communications, the odds are it's going to be going via a third party. Next time you send an email, tell the recipient that from now on you're going to communicate directly by TLS, and they'll need to set up a server before you can talk to them again. I believe that most people will have considerable difficulty doing that.
So, you're reliant on third parties who constitute single points of failure and potential targets of legal action.
Individuals who can securely set up TLS (or PGP or whatever) for their own communications are sufficiently rare that they effectively don't matter.
For hosting provider setup, to domain name registration and TSL certificate generation there are thousands of online tutorials.
You don't need to be an expert or a developer to know how to setup TLS on a Wordpress blog.
This isn't really about stopping that though, it's about the snooping nanny state plain and simple.
I think you're severely underestimating the intelligence of people in general. If we're talking about ISIS, all it takes is one moderately experienced computer user to show everyone else how to use PGP.
And yet we find a bunch of supposedly encrypted stuff where the user did something wrong, leaving the stuff effectively unencrypted.
See also people uploading keys to github etc.
I suppose I omitted the step of copying and pasting your recipient's public key, but that's not especially conceptually difficult, either.
There's also keypair generation, which is the step that derails most people I think. Plus the fact that people have to grok the concept of public and private keys, and be able to distribute / not distribute them as appropriate. And revocation certificates. And public keyservers. And trust levels. Etc.
I do think an organised, disciplined group might manage to get PGP working as intended, but I doubt there are many such groups.
My point is, I doubt individuals implementing encryption have much to fear from whatever proposals may emerge from this. Maybe they will later. But it seems to me it's much more likely to target companies that offer/facilitate encrypted messaging.
Edit: Thanks to whoever just put my karma over 2000. Does anything exciting happen when you get to 2000 points?
Obviously, that's total conjecture, though.